fecal incontinence

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http://www.mayoclinic.com/health/fecal-

incontinence/DS00477/DSECTION=causes

Fecal incontinence

ARTICLE SECTIONS

Definition

Symptoms

Causes

Risk factors

Complications

Preparing for your appointment

Tests and diagnosis

Treatments and drugs

Lifestyle and home remedies

Coping and support

Prevention

Causes

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Bowel function

Critical to normal bowel function are:

Anal sphincter muscles. External and internal anal muscles contract

to prevent stool from leaving your rectum.

Rectal sensation. This feeling warns you to go to the toilet.

Rectal accommodation. Rectal stretching allows you to hold stool for

some time until you can get to a toilet.

The ability to hold stool requires the normal function of your

rectum, anus and nervous system. In addition, you must have the

physical and mental capabilities to recognize and appropriately

respond to the urge to defecate. If something is wrong with any of

these factors, fecal incontinence can occur.

A broad range of conditions and disorders can cause fecal

incontinence, including:

Constipation. It's ironic, but a common cause of fecal incontinence

is constipation. That's because chronic constipation may lead to

impacted stool — a large mass of dry, hard stool within your rectum.

This mass can be too large for you to pass, and as a result, the

muscles of your rectum and intestines stretch, and then eventually

weaken. Watery stool from farther up in the digestive system may move

around the hard mass and leak out, causing fecal incontinence.

Besides causing the muscles of your anus to stretch and weaken,

chronic constipation may also make the nerves of the anus and rectum

less responsive to the presence of stool in the rectum. Additionally,

weakened muscles don't move stool as efficiently through the

digestive system.

Diarrhea. Solid stool is easier to retain in the rectum than is loose

stool, so the loose stools of diarrhea can cause or worsen fecal

incontinence.

Muscle damage. Often, the cause of fecal incontinence is injury to

the anal sphincter — the rings of muscle at the end of the rectum

that help hold in stool. If these muscles are damaged, they're simply

not strong enough to hold stool back properly, and some may leak out.

This kind of damage can occur during childbirth, especially if you

have an episiotomy or forceps are used during delivery. However, such

damage may not be evident until years later.

Nerve damage. If the nerves that control the anal sphincter or those

that sense stool in the rectum are damaged, fecal incontinence can

result. Nerve damage can be caused by childbirth, constantly

straining when having a bowel movement, spinal cord injury and

stroke. There also are diseases that can affect these nerves, such as

diabetes and multiple sclerosis, and cause damage leading to fecal

incontinence.

Loss of storage capacity (accommodation) in the rectum. Normally,

your rectum stretches to accommodate stool. If your rectum is scarred

or your rectal walls have stiffened from surgery, radiation treatment

or inflammatory bowel disease, such as Crohn's disease or ulcerative

colitis, the rectum can't stretch as much as it needs to, so excess

stool leaks out.

Surgery. Surgery to treat hemorrhoids — enlarged veins in the rectum

or anus — can damage the anus and cause fecal incontinence, as can

more-complex operations involving your rectum and anus.

Rectal cancer. Cancers of the anus and rectum can lead to fecal

incontinence if the cancer invades the muscle walls or disrupts the

nerve impulses needed for defecation.

Other conditions. If your rectum drops down into your anus (rectal

prolapse) or, in women, if the rectum protrudes through the vagina

(rectocele), fecal incontinence can result. Hemorrhoids may prevent

complete closure of the anal sphincter, leading to fecal

incontinence.

Loss of muscle strength with age. Over time, muscles and ligaments

that support your pelvis, as well as your anal sphincter muscles, can

weaken, leading to incontinence.

Chronic laxative abuse. Relying on laxatives to maintain regularity

can lead to incontinence.